1. Field of the Disclosure
The disclosure relates generally to apparatus and methods for completing wells for the production of hydrocarbons from earth formations
2. Description of the Related Art
Hydrocarbons, such as oil and gas, are recovered from subterranean formations from a well (also referred to as wellbore) or wells drilled into such formations. Hydrocarbons are typically present in the fluid trapped at various formation depths. Such fluid is generally referred to as the formation fluid. After drilling a wellbore to a selected depth, a casing is often placed in the wellbore and the space between the casing and the wellbore inside (commonly referred to as the “annuls”) is filled with cement. Often, hydrocarbons are trapped in spaced apart zones or segment of the formations surrounding the wellbore. Such zones are referred to as production zones. In horizontal wells, hydrocarbons are typically recovered at several (often 4-10) spaced apart sections or segments along the horizontal well. A production string is conveyed inside the casing to produce hydrocarbons from each zone. A production string may include a base pipe or tubing and various types of production equipment, such as sand screens, inflow control devices, flow control valves, etc. for each perforated zone. Before a production string is installed in the wellbore, casing and cement adjacent each zone is perforated and the adjacent zones are fluidly isolated from each other to allow the formation fluid to flow from each such zone into the production tubing. To perforate and isolate adjacent production zones, a downhole tool (also referred to as a bottomhole assembly or “BHA”) connected to a wireline is conveyed into the wellbore by pumping a fluid under pressure into the wellbore. The downhole assembly typically includes a plug, such as bridge plug, a setting tool for setting the plug at a selected location and perforating gun or tool uphole of the plug. The bottomhole assembly is conveyed adjacent the lowermost production zone, where the plug is set to isolate the wellbore beyond below or downhole of the plug location. The setting tool detaches from the plug during the setting of the plug. The zone (casing and the formation) above or uphole of the plug is the perforated using the perforating tool to produce the fluid from the reservoir adjacent the perforations. The power to the downhole tool is provided from the surface via conductors in the wireline. The wireline also includes communication links or conductors that may be utilized for transmission of data between the downhole tool and surface instruments. In commonly used systems, an operator, typically employed by a rig operator, controls the supply of the fluid into the wellbore by controlling pumps at the surface. Another operator, typically employed by a service company, controls the tension on the wireline during pumping of the fluid into the wellbore. The combination of the fluid flow rate and the tension on the wireline determined the rate of travel (travel rate) of the downhole assembly into the wellbore. The tension and pump rate are typically defined or agreed upon by the operators and then used to convey the downhole assembly to a selected depth, generally without real time knowledge or feed-back about the conditions of the wellbore at or near the location of the downhole assembly, which assembly may be traveling several hundred meters per hour. In deviated and horizontal wellbore, obstructions in the form of cuttings and sand are present on the low side of the wellbore. Such obstructions reduce the inner dimensions of the wellbore and when the downhole encounters such obstruction at relatively high travel rates can cause the setting tool in the downhole tool to set the plug prematurely. Excessive travel rate, vibration, acceleration or a combination of such parameters of the downhole tool can also prematurely set the plug, cause the wireline to be detached from the downhole tool and can be detrimental to the health of the downhole tool downhole.
The present disclosure provides apparatus and methods for determining wellbore conditions during pumping of a downhole assembly coupled to a conveying member into a wellbore and for controlling and/or optimizing pump rate and tension on the conveying member for controlling the feed rate of the downhole assembly into the wellbore.